The invention relates to a light barrier arrangement which is able to monitor its own contamination.
When light barriers are used in situations where they are exposed to a considerable risk of contamination, it is often advantageous to provide an arrangement by which they are able to monitor their own contamination. This means that on exceeding a particular contamination level, which is preferably adjustable, a warning signal is emitted whilst the light barrier is still functioning perfectly. On the basis of this warning signal, the light barrier can be cleaned before it finally fails.